In the absence of epidemiologic data, it is difficult to make precise quantitative assessments of cancer risks in the human population attributable to environmental exposures to specific substances. This is because of the limited scientific information that is available to guide extrapolations from qualitative observations of carcinogenicity in bioassys with experimental animals to probable cancer risks in humans. This project seeks to acquire some of the information necessary to facilitate quantitative comparisons of this type concerning endometrial and cervical cancers between humans and 3 rodent species typically used in carcinogenesis bioassays. The human and rodent cervical and endometrial tissues will be compared with regard to their capacities to metabolize carcinogens, the resulting binding of carcinogens to DNA, their capacities to repair DNA damage, and their ability to generate mutagens from procarcinogens. These studies may reveal whether differences in tissue differentiation have a greater effect on carcinogenesis-related properties (metabolism, binding, DNA repair, and mutagenesis) than do differences in species. This information also may suggest the relative importance of intrinsic properties of a tissue and related factors like hormonal status versus extrinsic exposures to carcinogens as determinants of carcinogenesis in endometrium and cervix.